Class MagicDetector

Content type detection based on magic bytes, i.e. type-specific patterns
near the beginning of the document input stream.
Because this works on bytes, not characters, by default any string
matching is done as ISO_8859_1. To use an explicit different
encoding, supply a type other than "string" / "stringignorecase"

detect

Detects the content type of the given input document. Returns
application/octet-stream if the type of the document
can not be detected.

If the document input stream is not available, then the first
argument may be null. Otherwise the detector may
read bytes from the start of the stream to help in type detection.
The given stream is guaranteed to support the
mark feature and the detector
is expected to mark the stream before
reading any bytes from it, and to reset
the stream before returning. The stream must not be closed by the
detector.